Summary: Chronic infection with the hepatitis C virus (HCV) is a major cause of cirrhosis, decompensated liver disease and hepatocellular carcinoma (HCC) worldwide. Globally there are an estimated 72 million persons with HCV. In the United States (U.S.), 1% of the general population or 2.7 million persons have chronic infection based on the detection of HCV RNA in serum. In 2014, chronic HCV infection was the leading infectious cause of death in the U.S. These figures underscore the magnitude and impact that chronic HCV infection has on global and US public health. The treatment of chronic HCV infection has been revolutionized with the development of direct acting antiviral (DAA) agents. For most genotypes response rates to treatment now approach 90-95%. What remains unclear is the long-term outcome of patients who are treated with DAAs. In particular, what proportion of patients continue to progress, what is the incidence of hepatocellular carcinoma and how quickly does liver fibrosis/cirrhosis regress are important questions that remain to be answered. Chronic HCV is also associated with a number of extrahepatic complications including diabetes, cardiovascular disease and malignancies such as B-cell lymphomas. Whether the risk of these complications decline after successful eradication of HCV is unknown. Hypotheses/problems addressed: 1) Define the host, viral and environmental factors that determine the outcome of HCV infection after virological cure. To address this problem, we have initiated a new study to prospectively follow a cohort of 350 subjects successfully treated with direct acting antiviral agents to define the long-term outcome of patients after eradication of hepatitis C virus. The two primary aims of the study are to determine prospectively the rate of clinical outcomes (ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, variceal hemorrhage), hepatocellular carcinoma, liver-related mortality and all-cause mortality in treatment recovered hepatitis C and to determine the proportion and rates of fibrosis regression in subjects after successful therapy of chronic hepatitis C. A major focus of the study will be to develop novel biomarkers and genetic predictors of liver-related complications including hepatocellular carcinoma. We have enrolled 74 patients to date. Patients will be prospectively monitored for 10 years for outcomes. Cases of HBV reactivation among patients with chronic HCV infection while undergoing therapy with direct acting antiviral agents have been reported in the literature. In collaboration with the University of Toronto, we have retrospectively assessed the rate and features of HBV reactivation in a group of 90 patients. Reactivation was noted in a single patient. 2) Assessment of cardiovascular risk after HCV eradication Hepatitis C virus (HCV) exploits the host lipoprotein pathway for its lifecycle. Consequently, patients with chronic HCV have hypolipidemic profile. This observation suggests that sustained eradication of HCV might lead to dyslipidemia and increase risk for cardiovascular disease. Serial lipid panels and NMR-based lipoprotein profiles were assessed at multiple timepoints from fasting chronic HCV patients participating in a study evaluating sofosbuvir/velpatasvir for 12 weeks were evaluated. We have previously demonstrated a marked rise in all lipoprotein parameters within the first 7 days of antiviral treatment associated with viral clearance. The increase in LDL and more importantly small LDL (the most atherogenic particle) persisted 24 weeks after treatment was stopped. As a follow-up we have shown by qPCR using paired liver biopsy samples that rapid clearance of HCV from hepatocytes appears to upregulate cholesterol, lipoprotein and fatty acid biosynthesis through induction of key regulators of lipid and lipoprotein metabolism. These results suggest that patients should be evaluated for cardiovascular risk post-SVR and assessed for lipid lowering therapy. 3. Elucidate the role of microbiome in development of outcomes in patients with chronic HCV infection after anti-viral therapy There is a symbiotic relationship between gut microbiota and the host. Humans harbor 110 intestinal bacteria for each human cell. Although each persons microbial profile is distinct, the relative abundance and composition of bacterial species are similar among healthy individuals. The intestinal microbiome plays a major role in the pathogenesis of liver disease. Dysbiosis, or an imbalance of pathobionts and beneficial bacteria can result in deleterious effects on the host. Dysbiosis has been associated with worsening fibrosis/cirrhosis in a number of chronic liver conditions. As part of the natural history study after virological cure in we will be investigating the association between changes in the gut microbiome over time and correlating that with changes in hepatic fibrosis based upon two liver biopsies performed before and 5 years after antiviral therapy.